Stackable rolling rack apparatus

ABSTRACT

A stackable rolling rack apparatus capable of being stacked on a similar rolling rack apparatus includes a base unit having a generally horizontal frame assembly and a plurality of upright side members. Wheels are mounted to the base unit and extend below the lower surface of the frame assembly. Mounting plates are attached to the base unit such that upon stacking each mounting plate cooperatively engages an upright side member of the lower similar rolling rack apparatus. The apparatus includes support assemblies pivotally connected to the base unit. Each support assembly has an upright position and a lowered position. In the upright position each support assembly extends vertically above an upper end portion of the upright side members, and in the lowered position each support assembly is lower than the upper end portion of the upright side members.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/623,029, filed Oct. 28, 2004.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to portable rolling rack apparatus for supporting various items, as for example a number of pipes, and more particularly relates to portable rolling rack apparatus having upright supports members for supporting various items with the rolling rack apparatus being stackable for ease of storage or shipping.

2. Description of the Related Art

There are many prior art rolling dollies, carriages and rack apparatus in existence which are used for a variety of purposes. There are many instances, such as for storage or shipping, in which it is desirable to be able to stack the rolling dollies, carriages and rack apparatus. Following are some prior art patents disclosing a variety of portable wheeled units having a stacking feature.

U.S. Pat. No. 5,445,396 to Sebor discloses a nestable dolly construction wherein the bottom surface or panel of each of a number of dolly devices have wheel wells to enable secure stacking of dolly devices.

U.S. Pat. No. 5,662,343 to Mogensen et al. discloses a container base structure having perpendicular fixing elements in the corners. The container base is designed to enable attachments of various types of side boards. U.S. Pat. No. 6,349,951 to Mogensen et al. discloses a stackable roller carriage having swingably mounted wheels. The corner of the carriage unit is provided with a circular pocket which enables the carriage wheels to be received in the pocket regardless of their pivotable positioning.

U.S. Pat. No. 5,711,540 to Nesting discloses a roller carriage having pivoted casters at one end and fixed casters at the opposite end. The roller carriage has a retention device to retain the swingable wheel or wheels on an overlying roller carriage to thus permit stacking of the carriage units.

U.S. Pat. No. 6,257,152 to Ching-rong Liu discloses a wheeled pallet structure that is designed to enable stacking of the pallets.

In addition to having a rolling stackable unit, it is often desirable to have upwardly extending support members or uprights extending from a lower wheeled horizontal base structure. In such instances it adds difficulty and complexity to being able to stack the rolling units with ease and without disassembly.

U.S. Pat. No. 5,718,441 to Kern et al. discloses a display cart having wheels or casters that is designed for stacking. The wheels or casters are located on the underside of a base unit and are removably connected to opposed ends of the base unit. Upright support members are mounted to the base unit and shelf members are adapted for attachment to the upright support members. The base unit of the display cart is designed for stacking of the wheeled base units, however, the upright members and shelf members must be disassembled and removed from the base unit to enable stacking of the base units.

It is desirable to have a portable rolling unit having upright support members which can be stacked onto similar portable rolling units with ease and minimal difficulty. It is further desirable to have a stacking, portable rolling unit having upright support members in which the upright support members can remain attached to the unit when in the stacked position.

BRIEF SUMMARY OF THE INVENTION

The present invention includes a small portable rolling rack apparatus having a base unit and upright members. The rack apparatus is adapted to stack onto a similar rack apparatus. Preferably, the rolling rack apparatus includes wheels or casters mounted to the base unit to enable the rack apparatus to be moved along a floor, such as a construction floor.

Preferably, the base unit includes four corner uprights. In one embodiment of the present invention, the upright members include laterally extending projecting arms for support, as for example to support a number of pipes.

Typically, to ship numbers of its pipe rack products the mobile pipe rack apparatus are stacked and are typically encapsulated in a plastic sheath or are otherwise secured in stacked or nested relation. For stacking, the wheels or casters are typically removed. They can easily become lose or damaged when removed from the pipe rack cart.

The present invention of the rolling rack apparatus includes the following features that promote stacking or nesting of the rack apparatus while eliminating the need for disassembly of components and the potential for lost components. The upright members are pivotally mounted to the base unit to enable pivotal movement from an upright position to a lowered position for stacking. In the upright position, the upright members are preferably locked by spring-loaded pins. In the lowered position, the upright members are efficiently secured. The upper ends of the four corner uprights are received by rectangular holes in the caster mounting plates to assist in stabilizing the stacked or nested positions of the carts. The casters are mounted to the caster mounting plates so as to be located inboard of the corner uprights. This feature eliminates the need for removal of the casters when stacking.

Most importantly, no disassembly or unbolting is required on the part of the party receiving the stacked carts. Shipping costs are significantly low because the stacked or nested arrangement minimizes the space required for a number of stacked carts. To ready the pipe rack carts for use, the receive party will first unstack them. Then the uprights will be pivoted from the lowered position to the upright positions and locked by the spring-loaded pins. For storage by the user, the spring-loaded pins are moved to their unlocking positions by pulling on the rings. The uprights can then be pivoted to their lowered position.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

So that the manner in which the above recited features and advantages of the embodiments of the invention, as well as others which will become apparent, are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof documented in the drawings and accompanying text which follow. It is to be noted, however, that the drawings illustrate only typical embodiments of this invention, and are not to be considered limiting of its scope, for the invention admits to many other equally effective embodiments which vary only in specific detail. In the drawings:

FIG. 1 is a perspective view of a stackable rolling rack apparatus according to a first embodiment of the present invention, and showing a pair of upright members in an upright position;

FIG. 2 is a perspective view of a base unit of the stackable rolling rack apparatus of FIG. 1;

FIG. 3 is a plan view of a caster mount of the stackable rolling rack apparatus of FIG. 1

FIG. 4 is a perspective view of the rolling rack apparatus of FIG. 1 in a stacked position with the pair of upright members in a lowered position;

FIG. 5 is a perspective view of a second embodiment of the stackable rolling rack apparatus according to the present invention;

FIG. 6 is a perspective view of a third embodiment of the stackable rolling rack apparatus according to the present invention;

FIG. 7 is a perspective view of a fourth embodiment of the stackable rolling rack apparatus according to the present invention;

FIG. 8 is a perspective view of a base unit of the stackable rolling rack apparatus of FIG. 7;

FIG. 9 is sectional view of an extension lock assembly adapted for use with the fourth embodiment of the stackable rolling rack apparatus;

FIG. 10 is a perspective view of a fifth embodiment of the stackable rolling rack apparatus according to the present invention;

FIG. 11 is a perspective view of a base unit of the stackable rolling rack apparatus of FIG. 10; and

FIG. 12 is a sectional view of a spring-loaded plunger assembly.

DETAILED DESCRIPTION OF THE INVENTION

The stackable rolling rack apparatus according to a first embodiment of the present invention, generally designated as numeral 10, is shown in FIGS. 1-4. The rack apparatus 10 includes a base unit 12 having a pair of upright support assemblies 14 attached to the base unit 12. Preferably, four wheels, more preferably casters 16, are mounted to caster mounts 18 attached to the base unit 12. Preferably, at least two of the four casters 16 are swivel-mount casters.

As shown in FIG. 2, the base unit 12 includes a pair of transverse end members 20 a and 20 b transversely oriented relative to center rail 22, preferably a pair of center rails 22 a and 22 b. The end members 20 a and 20 b are preferably attached to the ends of the pair of center rails 22 a and 22 b. Preferably, the center rails 22 a and 22 b are parallel with each other and have a gap between them. At each end of the pair of center rails 22 a, 22 b, there is a pair of upright mounting plates 24 a and 24 b, and a transverse support plate 26. Each upright mounting plate 24 a, 24 b includes an hole 28 and a slot 30 which are in opposing relationship with the respective hole 28 and slot 30 of the opposing upright mounting plate. The transverse support plate 26 includes a cutout 27. As shown in FIG. 2, the transverse support plate 26 is attached to an end member 20 a or 20 b and is also attached to the pair of upright mounting plates 24 a and 24 b. The upright mounting plates 24 a and 24 b are also attached to center rails 22 a and 22 b, respectively. It is to be understood that the transverse support plate 26 provides lateral support for the upright mounting plates 24 a and 24 b.

Still referring to FIG. 2, preferably a spring-loaded plunger assembly 31 is mounted to one of the pair of upright mounting plates 24 a, 24 b. As shown in FIG. 12, the plunger assembly 31 includes a plunger housing 32 having a longitudinal throughbore 32 a and a reduced diameter opening 32 b forming an interior shoulder 32 c at one end of the housing 32. The housing throughbore 32 a receives a plunger 34 and a spring 33. The plunger 34 has a first portion 34 a and a second portion 34 b. The first portion 34 a has a diameter adapted to freely extend through the reduced diameter opening 32 b of the housing 32. The second portion 34 b has a diameter greater than the first portion 34 a although smaller than the diameter of the throughbore 32 a so that the second portion 34 b can be received within the housing throughbore 32 a. The transition from the first portion 34 a to the second portion 34 b defines an edge face 34 c. The spring 33 is installed onto the first portion 34 a of the plunger 34 and retained in compression between the plunger edge face 34 c and the housing interior shoulder 32 c. The free end of the plunger first portion 34 a includes a hole 34 d adapted to receive a pull ring 36 for pulling the plunger second portion 34 b into the housing throughbore 32 a.

Preferably, a base side member 38 is vertically mounted at or near the end of each of the transverse end members 20 a, 20 b. Preferably, the base side members 38 have a length equal to or greater than the height of the transverse support plate 26 and the upright mounting plates 24 a, 24 b for reasons which will be explained below.

As shown in FIGS. 1 and 2, the caster mounts 18 are attached to the lower surface of the transverse end members 20 a, 20 b, at or near the ends of the members. Referring to FIG. 3, the caster mount 18 preferably includes a plurality of holes 40 adapted to correspond with a plurality of holes 42 in a caster mounting bracket 44 (see FIG. 1). The casters 18 are preferably mounted to the base unit 12 with nuts and bolts inserted through the holes 40 and 42 of the caster mount 18 and caster mounting bracket 44, respectively.

As shown in FIG. 3, the caster mount 18 includes an opening 46. The opening 46 is sized and shaped so as to receive the upper end of the base side member 38 in the stacked position. It is to be understood that preferably the size and shape of the opening 46 is slightly greater than the size and shape of the base side member 38. It is also to be understood that the opening 46 is positioned axially below the upper base side member 38 to permit the stacking of similar rolling rack apparatus.

Referring to FIG. 1, the upright support assembly 14 includes an upright post 48 having one or more racks 50 transversely attached to the upright post 48. FIG. 1 shows three racks: a lower rack 50 a, middle rack 50 b, and upper rack 50 c. Preferably, each rack 50 has a rack support member 52 and a rack end member 53. The upright support assembly 14 is shown in the upright position in FIG. 1. In the upright position, the rack end member 53 preferably extends upwardly to prevent pipes or other objects stored on the rack 50 from rolling or sliding off the rack support member 52. It is to be understood that the rack support members 52 could all be the same length or can be different lengths as shown in FIG. 1.

In the preferred embodiment, the lower portion of the upright post 48 includes an upper hole 54 and a lower hole 56 extending through the upright post 48 as shown in FIG. 1. The spacing between the pair of upright mounting plates 24 a and 24 b is preferably slightly greater than the width of the upright post 48 which is received between the pair of upright mounting plates 24 a and 24 b. The upper hole 54 in the upright post 48 is adapted to receive the pin or plunger 34. A bolt 58 is inserted through the slots 30 of the pair of mounting plates 24 a and 24 b and the lower hole 56 of the upright post 48. Preferably, the bolt 58 is secured with a nut 60, more preferably a lock nut. Preferably, the spacing between the holes 54 and 56 is such that when the plunger 34 is in the upper hole 54, the bolt 58 is bearing against the lower end of the slot 30. This distributes the load carried by the upright support assemblies 14 to both the plunger 34 and the bolt 58.

Although not required, the present invention has been illustrated as being made from hollow tubing, and more specifically, square tubing. In such cases, it may be desirable to insert a cap 62 into the end of each tubular member as shown in FIG. 1.

The ability to fold and stack the rolling rack apparatus 10 will now be discussed with reference to FIG. 4. The pair of upright support assemblies 14 are lowered to their lower position by pulling on the plunger ring 36 and withdrawing the spring-loaded plunger 34 from the upper hole 54 of the upright post 48. This enables the upright post 48 to pivot about the bolt 58 in the slots 30 of the upright mounting plates 24 a, 24 b. The slots 30 allow the bolt 58 to move vertically along the length of the slots 30. This permitted movement within the slots 30 facilitates the pivotal movement of the upright support assembly 14 and also permits the upright support assembly 14 to pivot to a substantially horizontal lower position. Additionally, as shown in FIG. 4, the second upright support assembly 14 pivoted to the lower position comes to rest on top of the first lowered upright support assembly 14 as a result of the slots 30. It is also to be noted that the lowermost end 48 a of the upright post 48 extends through the cutout 27 in the transverse support plate 26 when in the lowered position.

With the rolling rack apparatus 10 in the lowered position, multiple rack apparatus 10 can be stacked on top of one another in a secure and compact fashion as shown in FIG. 4. The upper ends 38 a of the base side members 38 of the lower rack apparatus 10 are received in the caster mount openings 46 of the upper rack apparatus 10 which serves to secure the stack of rack apparatus 10. Since the base side members 38 have a length equal to or greater than the height of the transverse support plate 26 and the upright mounting plates 24 a, 24 b, the upper rack apparatus 10 is supported by the four base side members 38.

Thus, the present invention of the rolling rack apparatus 10 includes the following features that promote stacking or nesting of the rack apparatus 10 while eliminating the need for disassembly of components and the potential for lost components. The upright support assemblies 14 are pivotally mounted to the base unit 12 to enable pivotal movement from an upright position to a lowered position for stacking. In the upright position, the upright support assemblies 14 are preferably locked by spring-loaded plungers 34. In the lowered position, the upright support assemblies 14 are efficiently secured and are brought to rest on top of one another. The upper ends 38 a of the four base side members 38 are received by the openings 46 in the caster mounts 18 to assist in stabilizing the stacked or nested positions of the rack apparatus 10. The casters 16 are mounted to the caster mounts 18 so as to be located inboard of the base side members 38. This feature eliminates the need for removal of the casters 16 in order to stack the rack apparatus 10.

Additionally, no disassembly or unbolting is required on the part of the party receiving the stacked rack apparatus 10. Shipping costs are significantly lowered because the stacked or nested arrangement minimizes the space required for a number of stacked rack apparatus 10. To ready the rack apparatus 10 for use, the receiving party will first unstack them. Then the upright support assemblies 14 will be pivoted from the lowered position to the upright position and locked by the spring-loaded plungers or pins 34. For storage by the user, the spring-loaded pins 34 are moved to their unlocking positions by pulling on the rings 36. The upright support assemblies 14 can then be pivotally lowered.

A second embodiment of the rolling rack apparatus, generally designated 10′, is shown in FIG. 5. It is to be understood that the same reference numerals will be used for components identical with the rack apparatus 10 of the first embodiment, and the prime designation will be used with reference numerals for modified components. The rack apparatus 10′ is very similar to the rack apparatus 10 with the exception of the upright support assemblies 14′. Preferably, the base unit 12 is the same as described above with respect to rack apparatus 10 and thus will not be described again here.

The upright support assembly 14′ includes an upright post 48′ having an upper hole 54 and a lower hole 56. A cradle 51′ is mounted to the upper end of the upright post 48′. Preferably, the cradle 51′ is generally U-shaped to contain items, as for example pipes, supported within the cradle 51′. As shown in FIG. 5, a pair of support members 49′ may be attached to the cradle 51′ to provide additional stability and support to the cradle 51′. Preferably, the support members 49′ have a lower portion adapted to be received within the open upwardly-facing end of the base side members 38. Although not required, the cradle 51′ and support members 49′ may be made from hollow tubing. In such cases, it may be desirable to insert a cap 62′ into the upper ends of each tubular member.

The upright support assembly 14′ is attached to the base unit 12 in the same manner as discussed previously, i.e. via the plunger 34 and the bolt 58. It is to be understood that in the upright position, the lower portion of the support members 49′ are partially received upper ends 38 a of the base side members 38. When lowering the upright support assembly 14′ to the lowered position, the plunger 34 is removed from the upper hole 54 of the upright post 48′ and the upright support assembly 14′ is vertically raised to remove the lower portions of the support members 49′ from upper ends 38 a of the base side members 38. Once removed, the upright support assembly 14′ can pivot about the bolt 58 in the slot 30 to the lowered position. Although not shown, it is to be understood that the lowered position of the upright support assemblies 14′ is similar to that described above with respect to rack apparatus 10.

A third embodiment of the rolling rack apparatus, generally designated 10″, is shown in FIG. 6. It is to be understood that the same reference numerals will be used for components identical with the rack apparatus 10 of the first embodiment, and the double prime designation will be used with reference numerals for modified components. The rack apparatus 10″ is very similar to the rack apparatus 10 with the exception of the base unit 12″. Preferably, the upright support assemblies 14 are the same as described above with respect to rack apparatus 10 and thus will not be described again here.

The base unit 12″ is very similar to the base unit 12. The base unit 12″ includes a pair of base side rails 21 a″ and 21 b″ spanning between and connected to the ends of the transverse end members 20 a and 20 b. The pair of base side rails 21 a″ and 21 b″ provide additional structural rigidity and integrity to the base unit 12″. Optionally, it may be desirable to attach a screen 64″ to the base unit 12″. As shown in FIG. 6, the screen is preferably attached to the lower surface of the rails 21 a″, 22 a, 22 b and 21 b″, but could alternatively be attached to the upper surface of these members. The screen 64″ provides another surface on which to store items. All of the rest of the features of the rack apparatus 10″ are the same as the features of rack apparatus 10.

FIGS. 7 and 8 show a fourth embodiment of the rolling rack apparatus, generally designated 100. The rack apparatus 100 includes a base unit 112 and preferably four wheels or casters 16 mounted to caster mounts 18 attached to the base unit 112. As shown in FIG. 8, the base unit 112 includes a pair of transverse end members 120 a and 120 b transversely oriented relative to a center rail 22, preferably a pair of center rails 22 a and 22 b. The end members 120 a and 120 b are preferably attached to the ends of the pair of center rails 22 a and 22 b. Preferably, the center rails 22 a and 22 b are parallel with each other and have a gap between them. The base unit 112 preferably includes a pair of base side rails 121 a and 121 b spanning between and connected to the ends of the transverse end members 120 a and 120 b. The pair of base side rails 121 a and 121 b provide additional structural rigidity and integrity to the base unit 112. In the preferred embodiment, the side rails 121 a, 121 b are made from structural angle members. Preferably, a plate 164 or screen is placed on top of the rails 121 a, 22 a, 22 b and 121 b and the transverse end members 120 a and 120 b as shown in FIG. 7.

Referring to FIG. 8, the caster mounts 18 are attached to the ends of the transverse end members 120 a and 120 b in such a manner that the opening 46 extends beyond the end of the transverse end member 120 a, 120 b for reasons which will be explained below. Each transverse end member 120 a, 120 b preferably includes a pair of plunger assemblies 31 mounted thereto as shown in FIG. 7. Preferably, each plunger assembly 31 is the spring-loaded type as illustrated in FIG. 12 and discussed previously.

As shown in FIG. 7, a corner upright assembly 166 is adapted for attachment to each end of the transverse end members 120 a and 120 b. Each corner upright assembly 166 includes a first leg 168 joined to a second leg 170. The first leg 168 is adapted to be received in the end of the transverse end member 120 a, 120 b. The first leg 168 includes a hole 168 a adapted to receive the second portion 34 b of the plunger 34 upon insertion of the first leg 168 in the transverse end member 120 a, 120 b. The plunger 34 locks the first leg 168 in place with the second let 170 extending vertically. It may be desirable to include a plurality of holes 168 a in the first leg 168 so that the corner upright assembly 166 can be oriented such that the second leg 170 can be positioned horizontally alongside the plate 164 or extend horizontally in front of or behind the plate 164. Including a plurality of holes 168 a also permits each corner upright assembly 166 to be used at any corner of the base unit 112.

It may be desirable for the corner upright assembly 166 to include an extension member 172 as shown in FIG. 7. In such case, the second leg 170 preferably includes a pair of holes 170 a and 170 b near the upper and lower ends, respectively, of the second leg 170. The extension member 172 is sized such that it is capable of being received within the second leg 170.

Referring to FIGS. 7 and 9, the extension member 172 preferably includes a lock assembly 174 positioned in the extension member 172 near the lower end. The lock assembly 174 includes a sleeve 175 adapted to house a spring 176 compressed between a spring pin 177 and a lock pin 178 as shown in FIG. 9. The extension member 172 includes a hole 172 a therethrough. Each pin 177 and 178 includes a pair of teats 177 a and 178 a, respectively, on either side of a central body portion 177 b, 178 b. The central body portions 177 b and 178 b have a diameter greater than the teats 177 a and 178 a, respectively, but slightly less than the inside diameter of the sleeve 175. The diameter of the central body portions 177 b and 178 b is also greater than the diameter of the hole 172 a in the extension member 172.

As shown in FIG. 9, the sleeve 175 preferably has a length approximating the inside diameter of the extension member 172. The spring 176 has an inside diameter that is greater than the diameter of the teats 177 a and 178 a. The lock assembly 174 is installed by inserting the spring 176 in the sleeve 175 and compressing the spring by fully inserting the lock pin 178 and the spring pin 177 on either side of the spring 176. The entire assembly is then slid in the end of the extension member 172 and aligned with the hole 172 a. Once aligned, the outer spring teat 177 a fills the hole 172 a on one side of the extension member 172 and the outer lock teat 178 a extends through the hole 172 a and beyond the wall on the opposite side of the extension member 172. The enlarged diameter central body portions 177 b and 178 b are spring biased against the inside wall of the extension member 172.

Preferably, the teat 177 a of the spring pin 177 has a length no greater than the wall thickness of the extension member 172 while the teat 178 a of the lock pin 178 preferably has a length slightly greater than the combined wall thicknesses of the extension member 172 and the second leg 170 to provide locking engagement with the second leg 170 when the lock pin is aligned with either of holes 170 a or 170 b in the second leg 170. When the teat 178 a of lock pin 178 is received in hole 170 a, the extension member 172 is locked in its extended position. When the extension is not desired, the spring-loaded lock pin 178 is depressed and the extension member is further received in the second leg 170 and is locked in its retracted position when the lock pin 178 becomes aligned with hole 170 b. Preferably, the upper end of the extension member 172 is flush or slightly below the upper end of the second leg 170 in the retracted position.

It is to be understood that the rolling rack apparatus 100 is also adapted to be stacked on similar rolling rack apparatus. In such instances, the extension member 172 is in its retracted position and the upper ends of the second legs 170 are received within the caster mount openings 46.

FIGS. 10 and 11 show a fifth embodiment of the rolling rack apparatus, generally designated 200. The rack apparatus 200 includes a base unit 212 and preferably four wheels or casters 16 mounted to caster mounts 18 attached to the base unit 212. As shown in FIG. 11, the base unit 212 includes a pair of transverse end members 220 a and 220 b transversely oriented relative to a center rail 22, preferably a pair of center rails 22 a and 22 b. The end members 220 a and 220 b are preferably attached to the ends of the pair of center rails 22 a and 22 b. The base unit 212 preferably includes a pair of base side rails 221 a and 221 b spanning between and connected to the ends of the transverse end members 220 a and 220 b. The pair of base side rails 221 a and 221 b provide additional structural rigidity and integrity to the base unit 212. Preferably, a screen 264 or plate is attached to the base unit 212. As shown in FIG. 11, the screen 264 is preferably attached to the lower surface of the rails 221 a, 22 a, 22 b and 221 b, but could alternatively be attached to the upper surface of these members. The screen 264 provides a surface on which to store items.

A base side member 238 is vertically mounted at or near the end of the each of the transverse end members 220 a and 220 b. Preferably, a pair of gusset plates 280 are attached to each base side member 238, with one gusset plate 280 attached to a transverse end member 220 a or 220 b and the other attached to base side rail 221 a or 221 b. Preferably, an elongated slot 280 a is formed between each gusset plate 280 and the base side member 238.

Referring to FIG. 10, a pair of side walls 282, preferably made of screen, are adapted to hingedly attach to the base unit 212. Each side wall or screen 282 includes one or more hinge spacers 282 a spaced along the lower edge of the side wall 282. Preferably, a side support rod 282 b extends along the upper edge of the side screen 282 and includes downturned end portions 282 c adapted to be received within the open upper end of the base side members 238. A hinge rod 283 extends through the one or more side wall hinge spacers 282 a and the elongated slot 280 a in a corresponding pair of gusset plates 280 as shown in FIG. 10. The hinge rod 283 may be secured in place in a variety of ways well know to a person of ordinary skill. One such way is by drilling a hole through each end of the hinge rod 283 and inserting a cotter pin in the hole.

It is to be understood that the side walls 282 are adapted to pivot about the hinge rod 283 and fold down to a generally horizontal position. This is done by vertically lifting the side wall 282 to remove the downturned end portions 282 c from within the base side members 238 and then inwardly pivoting the side wall 282 about the hinge rod 283. The vertical lifting of the side wall 282 is made possible by the elongated slot 280 a which permits sufficient vertical travel of the hinge rod 283 to withdraw the downturned end portions 282 c.

Optionally, the side wall 282 may include a center support rod 282 d adapted to be received in a side support tube 284 mounted to the side rails 221 a and 221 b.

Preferably, a first end wall 286 and a second end wall 290 are hingedly attached to the base unit 212. The end walls 286 and 290 are preferably made from screen. The lower edge of the end walls 286 and 290 are pivotally connected to the transverse end members 220 a and 220 b. Preferably, each of the end walls 286 and 290 include a pair of plunger assemblies 31. It is to be understood that the plunger assemblies 31 can be of the type described above and shown in FIG. 12. The base side members 238 preferably include a plunger lock 238 a shown in FIGS. 10 and 11 as a pair of plates adapted to receive the second portion 34 b (FIG. 12) of the plunger 34. It is to be understood that the end walls 286 and 290 may also be folded to a generally horizontal position by withdrawing the plungers 34 from the plunger lock 238 a and pivoting the end walls 286 and 290 inwardly.

It may be desirable to include a handle 292 (FIG. 10) to one or both of the end walls 286 and 290 for facilitating maneuverability of the rolling rack apparatus 200. Another option which may be desirable is to attach a clevis 294 near the upper end of each of the base side members 238. The devises 294 can be used for purposes of lifting the rack apparatus 200.

It is to be understood that the rack apparatus 200 is stackable and the pair of side walls 282 and the end walls 286 and 292 are pivotally attached to the base unit 212 and pivot to a lowered position when stacking the units.

It is to be understood that the embodiments of the rolling rack apparatus described herein are all stackable without the disassembly or removal of casters or other components from the apparatus. Furthermore, the apparatus may be stacked two, three or more in height. It is also to be understood that the rack apparatus need not all be of the same type for purposes of stacking. For example, rack apparatus 100 could be stacked on rack apparatus 10′ which could be stacked on rack apparatus 10.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, but to the extent foreseeable, the spirit and scope of the invention are defined by the appended claims. 

1. A stackable rolling rack apparatus capable of being stacked on a similar rolling rack apparatus, the stackable rolling rack apparatus comprising: a base unit having a generally horizontal frame assembly and a plurality of upright side members, said frame assembly having an upper surface and a lower surface; a plurality of wheels mounted to said base unit, said plurality of wheels extending below said lower surface of said frame assembly; a plurality of mounting plates attached to said base unit, wherein upon stacking, each said mounting plate cooperatively engages an upright side member of the lower similar rolling rack apparatus; and a pair of support assemblies, each said support assembly pivotally connected to said base unit, wherein each said support assembly has an upright position and a lowered position, in said upright position each said support assembly extends vertically above an upper end portion of said upright side members, and in said lowered position each said support assembly is lower than said upper end portion of said upright side members.
 2. The apparatus of claim 1, wherein said plurality of upright side members are mounted on said upper surface of said frame assembly and said plurality of mounting plates are attached to said lower surface of said frame assembly.
 3. The apparatus of claim 1, wherein each said mounting plate has an opening vertically aligned with one said upright side member.
 4. The apparatus of claim 3, wherein each said mounting plate opening is slightly larger than said upper end portion of said upright side members.
 5. The apparatus of claim 3, wherein each said mounting plate opening is adapted to receive an end portion of one said upright side member upon stacking of the rack apparatus.
 6. The apparatus of claim 1, further comprising: said frame assembly having at least one longitudinal rail member having first and second ends; and said base unit including a plurality of upright mounting plates, at least one said upright mounting plate attached to said base unit at each end of at least one said longitudinal rail member, wherein each said support assembly is pivotally connected to at least one said upright mounting plate.
 7. The apparatus of claim 1, wherein each said support assembly in the upright position is locked in place with a spring-biased pin.
 8. The apparatus of claim 1, wherein each said support assembly remains connected to said base unit during the transition between the upright and lowered positions.
 9. The apparatus of claim 1, further comprising: said frame assembly having at least one longitudinal rail member having first and second ends; and a first pair of upright mounting plates attached to said base unit at said first end of said longitudinal rail member, and a second pair of upright mounting plates attached to said base unit at said second end of said longitudinal rail member, each said pair of upright mounting plates including a plunger assembly having a spring-biased pin for locking said support assembly in the upright position.
 10. The apparatus of claim 9, further comprising a pivot pin pivotally connecting one said support assembly to one said pair of upright mounting plates.
 11. A stackable rolling rack apparatus comprising: a base unit having a pair of transverse end members attached to opposite ends of at least one rail member, each said transverse end member having first and second ends, said base unit including an upright side member at each of said first and second ends of said transverse end members; a plurality of mounting plates, one said mounting plate attached at or near said end of each said transverse end member, each said mounting plate having an opening vertically aligned with one said upright side member; and a plurality of wheels, one said wheel attached to each said mounting plate.
 12. The apparatus of claim 11, wherein each said transverse end member has an upper surface and a lower surface and said upright side member is attached to said upper surface and said mounting plate is attached to said lower surface.
 13. The apparatus of claim 11, wherein each said mounting plate opening is sized to receive an end portion of one said upright side member.
 14. The apparatus of claim 11, wherein each said mounting plate opening is adapted to receive an end portion of one said upright side member upon stacking of the rack apparatus.
 15. The apparatus of claim 11, further comprising: said at least one rail member includes a pair of center rail members; said base unit includes a first pair and second pair of upright mounting plates, said first pair of upright mounting plates attached to said base unit at a first end of said pair of center rail members and said second pair of upright mounting plates attached at a second end of said pair of center rail members; and a pair of support assemblies, each said support assembly pivotally connected to one said pair of upright mounting plates.
 16. The apparatus of claim 15, wherein each said support assembly has an upright position and a lowered position, in said upright position each said support assembly extends vertically above the upper end of said upright side members and in said lowered position each said support assembly is substantially horizontal and lower than the upper end of said upright side members.
 17. The apparatus of claim 16, wherein said support assembly remains connected to said base unit during the transition between the upright and lowered positions.
 18. The apparatus of claim 16, wherein each said pair of upright mounting plates includes a plunger assembly having a spring-biased pin for locking said support assembly in the upright position.
 19. The apparatus of claim 16, further comprising a bolt connecting said support assembly to one said pair of upright mounting plates, said bolt providing a pivot connection between said support assembly and said pair of upright mounting plates.
 20. The apparatus of claim 19, wherein each said pair of upright mounting plates includes a plunger assembly having a spring-biased pin for locking said support assembly in the upright position. 